The aim of this research is to evaluate the Transdermal Dosimeter TDD as a new sensor to measure alcohol consumption. The long-term objective is to determine the value of the TDD in clinical practice and research, where it could provide a valuable new tool for the early diagnosis of alcohol abuses and measuring the efficacy of treatment. Rationale: The TDD is a small round adhesive device which is worn on the skin for up to eight days, where it collects transdermally excreted fluid at a steady rate. If alcoholic beverages are consumed while the TDD is worn, ethanol excreted in the transdermal fluid is trapped in the TDD by chemical adsorption. The presence of ethanol in the TDD indicates that the wearer has consumed alcoholic beverages, and the concentration of ethanol varies with the amount consumed. Experimental method: 25 alcohol abusers and 25 'social drinkers' will be studied as out-patients for an eight-day period. Alcohol drinking during this time will be monitored in three separate ways: 1) self-reports: All subjects will keep a detailed diary of their alcohol drinking.2) TDD'S: A total of 12 TDD's will be affixed to the skin on day zero; three of these TDD's will be removed on days 2,4,6 and 8, and assayed for ethanol.3) Complete urine collections will be obtained, using a condom catheter draining to a bag worn on the leg. The catheter will be changed daily, and the collected urine assayed for ethanol. Data will be analyzed to determine (a) the sensitivity, specificity and reproducibility of the TDD ethanol level as a marker of alcohol consumption, and (b) the correlation between mean ethanol levels measured in the urine and in the TDD.